#ifndef TVInputFile_hxx_seen
#define TVInputFile_hxx_seen

namespace COMET {
    class IVInputFile;
    class ICOMETEvent;
}

/// An abstract base class for input files that produce ICOMETEvent objects.
/// There are currently two derived class ICOMETInput which is the normal way
/// to read an offline event file, and IMidasFile which is the normal way to
/// read a MIDAS .mid file and convert the raw data into ICOMETEvent objects.
class COMET::IVInputFile {
public:
    IVInputFile() {};
    virtual ~IVInputFile() {};

    /// Return the first event in the input file.  If the file does not
    /// support rewind, then this should throw an exception if it is called a
    /// second time.
    virtual COMET::ICOMETEvent* FirstEvent() = 0;

    /// Get the next event from the input file.  If skip is greater than zero,
    /// then skip this many events before returning.
    virtual COMET::ICOMETEvent* NextEvent(int skip=0) = 0;

    /// Return the position of the event just read in the file.  A position of
    /// zero means that the first event was read.  A position of -1 means that
    /// no events have been read and we are not at the end of file.  The
    /// maximum position is the total number of events in the file.
    virtual int GetPosition(void) const = 0;

    /// Flag that the file is open.
    virtual bool IsOpen() = 0;

    /// Flag that the end of the file has been reached.
    virtual bool EndOfFile() = 0;

    /// Close the input file.
    virtual void CloseFile() = 0;

    /// Return the filename if it is available.  The name of the file is
    /// returned.  If the name is not available, this returns an empty string.
    virtual const char* GetFilename() const;

};

#endif